Automatic fire alarm



(No Model.) 2 Sheets-Sheet 1..

J HILL..

- AUTOMATIG PIRE ALARM. No. 295,760. Patented- Mar. 25`,\1 N173!84.

(No Model.) ,v 2 sheets-sheet 2.-

- J. HILL.

" AUTOMATIC HRB ALARM.

No. 295,760. Patente@ Mar. 25, 1884.-. -4

N. PETERS. Phon-Lilhngmphon washi nnnnnnnn C.

` l, showing the circuit open.

` UNrrED STATES PATENT @Erica JOHN HILL, or oOLUMBUs, GEORGIA.

AUTOMATIC FIRE-ALARM.

SPECIFICATIONIorming part of Letters Patent No. 295,760, dated March 25, 1884.

Application filed Septemb T0 @ZZ whom, t may con/cern:

Be it known that I, JOHN HILL, a citizen of the United States, residing at Columbus, in the county of Muscogee and State of Georgia, have invented new and useful Improvements in Automatic Fire-Alarms, of which the following is a specification.

This invention relates to improvements in fire-alarms, and has for its object to provide novel, simple, and efficient means for automatically closing an 'electric circuit by the generated heat of a coniiagration, thereby sounding` an alarm.

To this end my invention consists in the combination of devices hereinafter described and claimed, reference being had to the accompanying drawings, illustrating the invention, in which- Figure lis a plan-of the case or box inclosing the automatic circuit-closing apparatus. Fig. 2 is a central longitudinal section of Fig. Fig. 3 is a similar section, showing the circuit closed. Fig. et is a plan view of the inclosing-case shown in Figs. 2 and 3 inverted. Figs. 5, 6, 7, and 8 are plan and side elevations, respectively, of the electric connections contained within the casing. Figs. 9 and l0 are central sections of the inclosing-case, showing a modified form of the copper disk with the manner of attachs ing the same to the case. Figs. 1l and 12 are sections of the copper disk detached, showing its form before and after attachment to the case. Fig. 13 is a section of the circuit-closer combined with a journal or other bearing.

n The device which forms the subj ect-matter of this application consists of an outer box or casing, a, with its open side lying upon a foundation or bedfplate, a', to which it is securely fastened, whereby said casing is completely closed, `with the exception of a single opening in the top of `said casing, which is adapted to receive a fusible solder joint and plug, x. At at one end of said casing, and arranged longitudinally therewith, I attach a flat strip. of conducting metal, L', having a platinum contact-point, g, near one end, which extends within the casing a, and is iirmly secured to the bed or back a by means of a screw, b,whieh also serves as a binding-post for the circuitwire c. The plate L may be provided with perforations to receive screws, whereby it is er 10, 1883. (No model.)

fastened to the upper casing, a, in which construction the single screw b will serve to attach said casing to the base or support a', as shown in Fig. 2. At the opposite end of said casing, and in the same longitudinal line with the' strip L', is placed an elastic conductingstrip, K, attached to said casing and to the back piece, c', in a manner similar to that already described in connection with the strip L', and having a contact-point, d, which is so arranged that when the strip K assumes its natural position said contact will rest upon the contact g. The second circuit-wire, c', is connected with the strip K by means of the binding-post b, which also serves to hold the casing a firmly in place upon the back piece, a. Screws may also be passed through the latter into the casing a, in order to make a close joint between the two and 'prevent the entrance of dust, the presence of which should be avoided in all apparatus of this class.

In the top of the case a, and directly in linel with the conducting-strips K L', is placed an annulus, V, which may be made of any suit# able material, that I prefer being a convex copper disk, as shown in Figs. 9 and l0, having its center removed so as to leave an opening about one-eighth of an inch in diameter. 'Ihis convex annulus is constructed in the following manner; A thin copper disk having a central opening is drawn by dies or other suitable means into a convex form, as shown in Figs. 9 and l1, its diameter being such that it will accurately fill the countersunk recess athe central opening in the disk being practically concentric with the opening c in the case a. A hollow punch having an outer diameter about equal to that of the disk is then placed upon it; and by a blow of amallet the outer annular portion of the convex disk is attened, as shown in Figs. 10 and l2. By this operation the edge of the disk, which is expandedradially, is driven into the wood of the case c, fastening the disk iirmly in place and sealing the case against the entrance of dust. The central portion of the disk is left convex and {project-ing somewhat above the top of the casing. rIhe opening as in the case ais concentric with that in the annulus XV, but of smaller diameter. It will be noticed that theIeiid of the strip K projects some little distance beyond the contact-point d, and upon IOO the upper face of this projecting end is mounted a cylindrical projection, Y, considerably smaller than the opening in the casing, but too large to pass through that in the annulus NV. The contact-points d and y, being separated by raising the elastic strip l, the projection Y is forced up into the aperture in the case a and against the lower face of the annulus XV. XVhile in this position av drop of solder, rv, is allowed to lall into the opening in the annulus, through which it passes until it comes in contact with the project-ion Y, to which it attaches. The solder-plug, upon becoming solid, as it does almost instantaneously, sccurely holds the strip li in the position shown in Fig. 2, thereby keeping the circuit permanently broken at that point. lVhenever said plug is fused, however, the projection Y is released, and the elasticity of the strip K immediately brings the contact-point d down upon the point g, thereby closing the circuit and giving the alarm. Attention is called to the fact that the application of the solderplug X seals the casing a., tightly closing the only aperture lel't therein after it is applied to the back piece, a.

The solder-plug X is made of a combination of various metals, the object thereof being that it shall fuse at a comparatively low temperature, ranging from Il()o to 212o Fahrenheit. l-Ieretoiiore a composition has been used lconsisting of lead, tin, and cadmium, which would melt at 1550 to 1600 Fahrenheit, and in localities where fusion is not required at lower tcmperaturcs, I use the saine. In many places, however, a much lower fusion-point is desirable, ranging as low as 11.00 Fahrenheit. For the latter temperature I use a composition consisting oi the several metals named above, with a small portion of mercury, and thereby obtain a solder which will readilyT fuse at temperatures far below any composition heretol'orc made and used for this purposeHviz., Il()0 to l-lOO Fahrenheit. rIhe quantity of mercury employed depends upon the point at which fusion is required, the greater the proportion thereol' the lower being the point of fusion. By setting the solder-plug in a thin copper disk and blackening the latter, rapid absorption of heat is obtained, and the automatic circuit-closer is rendered more rapid and reliable in action.

rIhese devices may be scattered in as many localities as may be desired, the wires c and c being connected to the wires of the main circuit, or to branch wires leading therefrom. The breaking out of a fire at any one of these points creates suilicient heat to fuse the solderplug and release the spring-connection K, which at once falls upon the connection` L', cach arm having a contact-point. The circuit is thereby closed and the current flows from battery over the line, actuating th'e electric alarms interposed in the circuit.

Although I preferably use the thin convex disk shown in Figs. 9, 10, Il, and 12, I may use the flat copper annulus IV shown in Figs.

l, 2, and rlhe thin convex dish named may be pressed into the recess c and secured without expansion by being simply cemented in I place; or a projection may be substituted -for the recess, and the edges ci' the disk iitted around such projection as a band, and be thus secured in place. 1

Although these circuit-closers are adapted for general use to indicate the outbreak of fire, sound the alarm, and designate the locality in the manner described in my application for Letters Iatent iiled upon the 22d day of May, 1883, there are other and most important uses to which it may be put, of which the following is an example: It is well known that in all mills and large manufacturing establishments there are a great number of journal and other bearings which are not only secluded from observation, but which, from their number alone, cannot be constantly watched. It is a common occurrence for iii-es to ignite from the heat generated from friction at such points. Even when the damage resulting is not great, the loss of time in a large establishment from the stoppage of the machinery is a serious consideration. I propose, therefore, to use this sensitive circuit-closer at all points where there'is frictional contact which might, under favorable circumstances, heat the parts to the point of ignition of surrounding material, and to employ a fusible plug or solder-joint which shall melt at a point considerably below the point of combustion-as, for example, at 212 Fahrenheit. The circuit-closer may be attached to the journal-boxes or contiguously thereto in such manner that the heat therefrom may be communicated to the solder-j oint easily and without delay. Each bearing may be supplied with one of these circuit-closers, and thewires may be carried to any desired point where it is expedient to sound the alarm and designate the locality of the heating journals.

The casing c is closed and sealed, as already described, and is impervious to oil and water, as they are arranged in places where they may be subjected to and possibly covered with either.

Vith this invention, applied in the manner described, res from overheated journals will be practically impossible.

My invention may also be applied to railway-trains, to steamships, and other places.

lIhe size ol' the copper disk IV may, if required, be varied, the .apparatus being rendered :more sensitive by increasing its superlicial area within certain limits.

I also propose to use, in some instances, a metallic casing having insulated attachments for the electric connections, whereby oil will be wholly excluded from the interior of the casing a.

I am aware that it is not new in an autematic fire-alarm to hold an elastic conductor out of contact with a stationary conductor by means of fusible material; and such, therefore, I do not broadly claim.

IOO

IIO

Having thus described my invention, what I claim is 1. In an automatic iire-alarm, the combination of two conductors, one of which is composed of an elastic metal, with a metallic disk, means for supporting the disk in a stationary position at one side of the elastic conductor, and a fusible joint connecting the latter with the stationary disk, to hold the said elastic conductor out of contact With the other conductor, substantially as described.

- 2. An automatic circuit-closer contained in a closely-sealed case, and consisting` of electric connections which enter said case and are normally in contact, but which are held out of contact by a fusible plug which enters and seals an aperture in the top, from which it is exposed, substantially as described.

3. An automatic circuit-closing device, consisting of the conductors K and L, having suitable eontact-points, said points being contained Within a casing, a a, and being held out of contact by means of a fusible plug, X, eX-

posed upon the outside of said casing a, substantially as described.

4. The combination, in an automatic firealarm, of a oase having a recess, a sensitive disk having a convex center and a flat surrounding` margin, and arranged in the recess, the conductors, and a fusible joint, substan- 3o tially as described.

5. Ihe combination, in an automatic iirealarm, of a disk having a perforation, a conductor, L, havinga contact-point, an elastic conductor having a contact-point on one side 35 and a projection on the opposite side, and a fusible plug passing through the perforation in the disk for connecting the said projection with the disk, substantially as described.

In testimony whereof I have hereunto set my 4o hand in the presence of two subscribing Witnesses.`

` JOHN HILL. v Titnessesz G. GUNBY J oRDAN, E. P. BURNETT. 

